The main objectives of the proposed Research Training Program are (1) to foster the development of physician scientists and PhD scientists in pediatric cardiology, and (2) to encourage investigation of problems that are relevant to cardiovascular biology and, in particular, to developmental aspects of the cardiovascular system that are critical to heart disease in children. Trainees will be individuals with outstanding promise for research who exhibit a very high degree of motivation, intelligence, and potential for creativity and innovation, as well as a serious commitment to a career at the interface of research and clinical medicine. Candidates from underrepresented minority groups will be actively recruited. Most of the research fellows will be MDs with prior training in pediatrics, and pediatric cardiology. Some will have had previous research experience such as is obtained in an MD-PhD program. Other trainees will be recently graduated PhD scientists who are interested in pursuing postdoctoral training in one of the Program's laboratories. The training program will take place in the laboratories of the Department of Cardiology, as well as extramural laboratories at other area institutions, under the guidance of experienced preceptors. Most trainees will perform basic science research in the disciplines of molecular, cellular, and developmental biology and genetics, as well as protein chemistry, and immunology as they relate to the etiology and pathogenesis of cardiovascular disease. Clinical investigators in pediatric cardiology will be trained to become competent in study design appropriate for elucidation of particular clinical problems, biostatistical analysis, decision analysis and technology assessment, and data collection instruments and methods. Training will encourage the correlation of basic laboratory studies with clinical cardiology problems. Trainees will participate in didactic courses, research seminars, and journal clubs to help them develop a solid base of scientific knowledge and skills for critical reading of the literature. Excellent training in experimental bench research and rigorous prospective clinical investigation will prepare graduates of the Program to assume positions of leadership in pediatric cardiology and cardiovascular research.